July 24, 2007 by jimstogdill
Hacking Hardware for Software Control
Jonathan is apparently the McGyver of cyber/physical mashups and seems to have automated everything in or near his home: mailbox, lighting, blinds with motors, sprinkler systems (that check the weather and sample soil moisture before starting up), and etc.
What he demonstrated in the tutorial was a Second Life avatar actuating a real world appliance something like this… a scripted object in Second Life initiates an outbound HTTP connection when “touched” by an avatar. That outbound HTTP initiates a script on a remote webserver that talks to that machine’s USB serial port (that is a slight simplification, because he couldn’t get a fixed IP at OSCON there were actually two web servers involved). Connected to the serial port is an open source / open hardware Arduino (http://www.arduino.cc/) board.
The Arduino board was programmed so that one value on the serial port would actuate an attached relay, and a second value would actuate a second attached relay.
The relays were in turn connected to a busted open and hacked radio remote control to a cheap appliance store appliance controller. (this chain of Arduino to relay to appliance controller was all about pushing up the voltage and current that could ultimately be controlled – analogous to a remote controlled power breaker).
When it was all said and done, the Arduino board served as a virtual to real world “impedance matcher” (that is an analogy fraught with problems) and when the avatar touched the object (now a virtual light switch) the light on the desk went on or off depending on its previous state.
Seems like tons of things that could be done with this kind of connection. Some Arduino examples are here.